most businesses -- and again, technology smaller than a hockey puck. people see them if they are aware of them. the plexiglass dome can often contain three or four camera heads. sometimes led lighting at night. >> this is a radical change from five or six years a i go. all of our cities are wired. some of those will be the official cameras for say the boston police department. as you said, almost every business and every person. and that's why officials came out early on and said, please, turn this in. preserve it. otherwise the businesses might ordinarily lose that after a couple of days. so it needed to be preserved. get to the government. it takes time to get through all this. once you know about the location and timeframe, officials can get through that relatively rapidly. >> quite extraordinary yesterday. people taking the air shuttle and flying from boston logan to let's say, new york, were stopped. heard an announcement. before you leave here, ask yourself, do you have any evidence. did you take any pictures of the marathon? i arrived at the amt